Thanks for signing up! You might also like these other newsletters:

Eating plant foods and drinking fluids are a couple of things cancer patients can do to help the healing process.

Gillian Blease/Getty Images

Key Takeaways

Good nutrition during cancer treatment helps to ensure good health afterward.

Calories, protein, and plant foods are the building blocks of a good diet during cancer treatment, so be sure to get enough of each.

Drink plenty of fluids, as long as your healthcare provider says it won’t interfere with your treatment.

“Let food be thy medicine.” — Hippocrates

For the person undergoing cancer treatment, this well-known health motto rings true. Fortifying the body with a wholesome diet that provides adequate nutrition is crucial during this challenging time.

“When we talk about nutrition during cancer treatment, it’s important to understand that nutrition itself is not going to be a treatment — we don’t have any evidence of that,” says Karen Collins, RD, nutrition advisor to the American Institute for Cancer Research.

What following a healthy diet will do is “help the patient maintain healthy body composition, promote success of the medical treatment of cancer, and put them in a good position after treatment,” says Collins.

The following nutritional building blocks can help make this possible.

Get an Appropriate Number of Calories

One of the main nutrition goals for cancer patients is maintaining a healthy body weight.

“Typically, people with cancer undergoing treatment are going to lose weight,” says Danielle Kennedy, RD, a certified specialist in oncology nutrition with the Cancer Treatment Centers of America at Eastern Regional Medical Center in Philadelphia. “We want to proactively nourish the body. Our objective is to deter weight loss as much as possible.”

But the days of serving cancer patients unlimited quantities of ice cream are long gone. Instead of just looking to get any calories into the patient, the goal is to have them consume calories that are rich in nutritional value.

Because it's often difficult for cancer patients to eat large meals, foods that pack a lot of calories and nutrients into a small serving are ideal. These include:

“When patients are unable to get adequate protein from the foods they eat, another option is a high-protein supplement, which is available in a liquid or powdered form," says Dr. McLymont. “Most powders are tasteless, so they can be added to different recipes without changing the flavor of the food.”

McLymont suggests choosing powdered protein supplements over ready-to-drink liquid protein supplements, because patients may feel full too quickly with the liquids before they consume all the protein they need.

Eat Plant Foods

Plant foods, which include fruits, vegetables, legumes, and whole grains, are rich in vitamins and minerals — some of which are antioxidants. These compounds, found naturally in foods, may support health by blocking damage caused by harmful molecules in the body called free radicals — damage thought to be involved in the development and the treatment of some cancers. In addition, these compounds can help nourish your body, and may help it heal during this time.

“A lot of questions are being raised about antioxidants during cancer treatment,” says Collins. “The way radiation works is by creating free radicals that kill cancer cells. Some people have the mentality that if some is good, more is better — and they drink blueberry smoothies five times a day.”

“But it’s not clear whether this could help by reducing damage to healthy cells during treatment, or where a line might be crossed when it starts working against their treatment,” she says. “It's possible that it could help reduce damage to healthy cells, but we don't have evidence to support that strategy.”

Collins advocates a more conservative approach focused on variety. “Until we have a better answer, it makes sense to eat healthfully: an abundance of fruits and vegetables, whole grains, beans, nuts, and seeds if they’re tolerated, without being excessive about any of them.”

Drink Plenty of Fluids

Staying hydrated is another nutrition goal for people undergoing cancer treatment.

“We push lots of water,” says Kennedy. “A lot of our patients are easily dehydrated because they’re malnourished or may become malnourished. Additionally, if they’ve experienced constipation or a lot of diarrhea, they need more water.”

As a general rule, drinking eight 8-ounce glasses of water or decaffeinated beverages each day, and eating plenty of fruits and vegetables — which have a high water content — should meet most individuals’ fluid needs.

Some conditions, however, may call for fluid restriction; patients should follow the advice of their healthcare provider for their individual nutrition and fluid needs.